I am different from you. Totally opposite to be exact. I am from Vietnam and care a lot for my children's education. I am preparing for my children's overseas university (although I wish them would study overseas from much younger age, I can't afford). In doing so, I do learn a lot about education either in Vietnam and neighbourhood countries.
If you don't mind or prefer sending your kids to local schools then I would recommend you check out the Asian International School or the Vietnam Australia School (sounds like but similar to AIS but double the cost, you probably prefer this one) because it's a local school with local students and provides local education as well as English language, math/science/drama/ etc in English. its teaching method is more creating students own opinion in contrast to 100% local schools where students being told or allow certain things and what to do. No creative at all. AIS is not the best but should meet most of your expectation in many aspects.
Education system differential between local and Canada isn't great, the most concern should be language barrier so:
If your kids study at 100% international school them they can go straight away to uni in Canada as their English good enough
If your kids study at local with English, I reckon they should go back Canada at least in the last 11th and 12th grade to ensure thwy could catch up their efficient English to enter uni
If your kids study at 100% local schools then they should go back Canada in their 7th or 8th grade.
I agree with you to give them the idea that life is...... especially when they take their class locally to see life in Vietnam as well as seeing how lucky they are that should make them try harder
Since you are working in Saigon centre and Saigon centre isn't great in size so wherever you stay, it should be around 15 - 30 minutes drive only. Where to stay depends on your family need and want and budget to, it can start from $500/month for a 2 bedroom house , from $1,200/month for a 3 bedroom house with swimming pool for instance. If you plan for fly very often then district 3,phu nhuan, go vap is an ideal as they are in the mis way between Saigon centre and Tan Son Nhat airport (go vap is lowest rental price). If you plan for going to Mekong in the weekend often then district 1,7,5 is an ideal or if you plan for going to Vung Tau, Mui Ne etc then district 1,2,Binh Thanh (Binh Thanh is lowest rental price).